Cardiac Defibrillator Implantation

Basic Facts

A defibrillator is a device that sends an electric shock through the heart muscle to halt an arrhythmia and restore a normal heartbeat.

An automatic implantable cardiac defibrillator, or ICD, is a small device that is implanted under the skin in the upper chest and connected to the heart with wires called leads. The ICD constantly monitors the heart rate and, when it detects an irregularity, the ICD electrically shocks the heart to normalize its rhythm.

People who have experienced cardiac arrest and certain people with a high risk of developing an arrhythmia called ventricular fibrillation are generally considered candidates for an ICD.

The implantable cardiac defibrillator is similar to a pacemaker. Pacemakers are commonly advised for patients with unhealthy, slow heartbeats.

The implantable defibrillator is a bigger device and is placed in the body to help people who have life-threatening arrhythmias (heartbeat irregularities). It can deliver a low energy shock that can convert an abnormal rhythm back to a normal heartbeat, and it can send a high energy shock that is delivered only if the condition is so severe that the heart is quivering instead of beating (ventricular fibrillation).

The implantable defibrillator consists of a generator and a system of leads, or wires, which connects the generator to the heart. The generator is a smooth, lightweight metal case containing a tiny computer and a battery. The implantable defibrillator can:

Keep track of heart rhythms,

Send out electrical pulses and shocks when needed,

Record heart rhythm, and

Record the pulses and shocks the defibrillation device sends out.

The titanium implantable defibrillator is smaller than a cigarette lighter and is placed under the collarbone. The wire lead runs through a vein and into the heart, and the device tracks the heart's rhythm, activating when needed.

Cardiac Defibrillator Implantation FAQ

To diagnose the cause of heart rhythm problems and to determine whether or not a person is a candidate for an implantable defibrillator, the physician may order one or more of the following tests:

Electrocardiogram (ECG) – This noninvasive test that records the electrical activity of the heart.

Echocardiogram – This test uses sound waves to create a moving picture of the heart, showing its size and shape, as well as how the heart chambers and valves are working.

Cardiac Catheterization - Cardiac catheterization involves the insertion of a thin tube called a catheter into an artery. The catheter is threaded through the arterial system to the arteries in the heart, where physicians use it to assess or treat cardiac problems.

Electrophysiology Study – The study produces a detailed evaluation of the heart’s electrical activity, using cardiac catheters and computers to create electrical measurements from inside the heart.

The patient is instructed not to eat or drink after midnight the day of the procedure. Patients who take daily medication should discuss with their physician whether or not the medication should be taken morning of the procedure.

An implantable defibrillator can be placed on the right or left side of a patient’s body. Patients should discuss any preference of placement.

During the procedure, the right or left side of patient’s body is shaved and cleaned from the neck to the groin. Monitors are attached to the patient’s body and the patient is started on an intravenous line to provide fluids, medications, and an antibiotic. Another line, inserted in an artery, may be used to monitor blood pressure and check the oxygen level in the blood during the procedure.

The patient is also connected to machines that monitor heart rate and electrical activity, show the leads on an x ray screen as they are guided into the heart, and, if necessary, help the patient breathe while he or she is under anesthesia.

When the procedure begins, the surgeon will make a small incision under the patient’s collarbone. A pocket-like space is made under the patient’s skin or muscle to hold the generator. The lead is placed into a vein, and then guided to the patient’s heart. The lead tip attaches to the heart muscle, and the other end is attached to the generator. The generator is set to treat heart rhythm problems and then is placed under the skin.

The incision is then closed and covered with a sterile dressing.

The procedure can take from two to eight hours and is often performed under general anesthesia.

Following the procedure, the patient will stay in the hospital for one or two days, depending on the type of implantation procedure. The patient’s heart will be monitored to make sure the defibrillator is working properly.

Before leaving the hospital, the physician will schedule 15- to 20-minute follow-up appointments, which are very important and should occur every two to four months.

Once home, the patient can usually resume most of his or her daily activities. The patient should avoid any strenuous activities for a couple of weeks. However, the patient should avoid raising that arm above his or her head on the side of the body where the device is implanted and should check the incision area every daily signs of infection.